Autism Symptoms Replicated in Mice with Gene Mutation
Researchers at Massachusetts Institute of Technology and Duke University have produced mice with two of the most common traits of autism – compulsive, repetitive behavior and avoidance of social interaction – by mutating a single gene called SHANK3. The identification of the first of the “single-gene knockouts” may help put scientists a step closer to understanding the genetic link to autism.
SHANK3 Mutations Interfere with Brain Cell Communication
Previously, scientists have identified genes and environmental causes that are linked to only a few specific traits related to autism, but this new model is the first to replicate the wider range of behavioral tendencies of autistic children.
The SHANK3 gene mutation has been identified in nearly 16% of children with autism. Shank proteins, located on chromosome 22, are involved in synapse formation and dendritic spine maturation. Mutations to the gene appear to produce autistic behaviors by interfering with communication between brain cells.
SHANK3 is also primarily found in a part of the brain called the striatum, involved in motor activity, decision-making, and the emotional aspects of behavior. Malfunctions in this area are not only implicated in autism, but also obsessive-compulsive disorder.
While the creation of a mouse with the SHANK3 genetic mutation does not ensure that any findings related to studies performed on the animal would be applicable to humans, the findings are a “big step” toward understanding autism.
"Having an animal model that can teach us more about how a specific gene mutation is correlated with behavior is critically important to our understanding of the overall biology of autism," said Andy Shih, vice president of scientific affairs at Autism Speaks.
About one in 110 children in the United States has an autism spectrum disorder, which can range in severity and symptoms but usually includes difficulties with language in addition to social avoidance and repetitive behavior. There are currently no effective drugs to treat autism.
"We now have a very robust model with a known cause for autistic-like behaviors," said senior author Guoping Feng, a professor of brain and cognitive sciences at MIT. "We can figure out the neural circuits responsible for these behaviors, which could lead to novel targets for treatment."
João Peça, Cátia Feliciano, Jonathan T. Ting, Wenting Wang, Michael F. Wells, Talaignair N. Venkatraman, Christopher D. Lascola, Zhanyan Fu & Guoping Feng. Shank3 mutant mice display autistic-like behaviours and striatal dysfunction Nature (2011), doi:10.1038/nature09965, Published online 20 March 2011